1. Field of the Invention
The present invention relates to a liquid crystal display device and a manufacturing method thereof.
2. Description of the Related Art
In recent years, a liquid crystal display device is used in a wide range of fields such as a liquid crystal television, a PDA, a mobile phone, and office automation equipment like a personal computer, as well as a clock and a calculator.
In a liquid crystal display device, liquid crystal is sealed between two substrates. When voltage is applied, an orientation of liquid crystal molecules is changed and light transmittance thereof is changed, so that an image or the like is displayed optically.
An image quality and reliability of the liquid crystal display device are largely affected by whether the two substrates are attached to each other with good adhesion with the same interval or not. A technique to reduce unevenness of a sealant caused by a wiring which is under the sealant by formation of a dummy wiring and to keep the interval between the substrates has been reported (see Patent Document 1: Japanese Published Patent Application No. H9-179130).
As a method for forming a liquid crystal layer in the liquid crystal display device, a dipping method in which liquid crystal is injected with the use of capillary phenomenon after attachment of a pair of substrates (also referred to as a pumping method or a vacuum injection method) and a liquid crystal dropping method in which liquid crystal is sealed by a dropping method are given. Time required for a process can be shortened and productivity can be improved in a liquid crystal dropping method as compared to a dipping method.
However, when a liquid crystal dropping method is used, since an uncured sealant and liquid crystal is in contact with each other, there has been a problem in that the liquid crystal is contaminated by the sealant and a sealant with little contamination of liquid crystal has been developed (for example, see Patent Document 2: Japanese Published Patent Application No. 2005-115255).